Celestron f/6.3 Focal Reducer for Schmidt-Cassegrains

Celestron f/6.3 Focal Reducer for Schmidt-Cassegrains

Due to high demand and global product shortages due to the pandemic, please call for availability.

The Celestron f/6.3 focal reducer and field flattener is a photographic accessory produces 37% wider fields of view. Exposure times are reduced by a factor of 3.

The resulting f/ratio of f/10 Schmidt-Cassegrains (8", 9.25" and 11" models) with the reducer is f/6.3. The resulting f/ratio when used with 14" Schmidt-Cassegrains is f/7.

The focal reducer threads onto the large 2" threads, in place of the visual back. Schmidt-Cassegrain standard t-adapters thread onto the end of the reducer.

The corrector capabilities help deliver rounder stars towards the edge of the field of view due to field curvature. Field curvature isn't eliminated, but reduced significantly.

Can be used visually, or photographically with DSLR's or film SLR's.


  • 4-element lens design
  • Makes SCT scopes one full f-stop faster
  • Reduces exposure time by a factor of 3 to capture the same brightness of object
  • Flattens field to deliver rounder stars towards the edge of field
  • Increases field of view by 37% to better capture wide field images
  • Threads directly onto the 2" threads of SCT's
  • Allows use of existing SCT T-adapters


  • Coatings: Fully Multicoated
  • Black anodized Aluminum housing
  • Rubber grip
  • F/stop reduction factor: 37%
  • Added length to scope: 24mm (.95")
  • Overall Length: 34mm (1.3")
  • Weight: 115g (4oz)
  • Made in China